Process of preparing alkyl compounds of lead



Patented Dec. 4, 1928.

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CHARLES A KRA'US AND CONRAL C. CALLIS, F WORCESTER, MASSACHUSETTS, AS-

SIGN ORS T0 STANDARD OIL DEVELOPMENT COMPANY, A CORPORATION OF DELA- WARE.

PROCESS OF PREPARING ALKYL COMPOUNDS OF LEAD.

N 0 Drawing.

This invention relates to the art of preparing alkyl compounds of lead. and will be fully understood from the followingdescrlption.

It has been heretofore shown that if small quantities of water be added to an alloy of lead and sodium in the presence of 'an alkyl iodid that a lead alkyl compound is formed in'small amounts. It has been supposed that the action involved here was of a catalytic character and that .the reaction soon reached an equilibrium which precluded anything over very trifling yields. We have now found that this reaction is not catalytic in character, but on the contrary that there is a direct propor onal reaction between the water and the sodium present in the alloy, and we have further found that by applying the water under proper conditions substantial yields of the lead alkyl compounds may be obtained. No organic catalyst is used.

In proceeding in accordance with this invention we use suitable alloys of lead and sodium, the sodium running between about 6% and 30%. Preferably an alloy of about 20% of sodium and 80% of lead is employed. The alloy suitably subdivided, for instance in about the size of wheat grains, is introduced into a suitable vessel, preferably one which is pressure resistant when closed tightly, and which is provided with stirring means, also temperature controlling means such for instance as jackets or coils. An alkyl halid, for example ethyl iodid, is also introduced and then water for instance, as decomposing agent, is fed in at a rate preferably such as to allow the reaction mixture to maintain the temperature at around boiling. If necessary, heat may be applied. The addition of Water is continued until no further reaction occurs, the final limit on the water being the molecular equivalent necessary to complete reaction with the amount of sodium presentin the alloy. While water is most readily available as the decomposing agent in'this reaction, other substances reactive upon the sodium may be equivalently employed, as for example alcohol or weak or diluted acids which are without material action upon the lead or the lead compound; acetic acid being quite advantageous. In all cases however the decomposing agent should be added in amounts molecularly equivalent to the sodicontainer.

will be understood that made which fall within the spirit and scope Application filed April 13, 1923. Serial No. 631,941.

um present in the alloy in order to obtain maximum yields. Hydrogen is generated. in the reaction and it is desirable to maintain the temperature rather closely Within the reaction range so as to maintain the pressure Within favorable limits.

The reaction being completed, steam is introduced into the reaction vessel through suitable perforated pipes and the lead tetraet-hyl formed in the reaction is distilled out with the steam and condensed in a suitable condenser. Since the lead tetraethyl is insoluble in and heavier than the water of condensation, it may be drawn ofl' separately from the bottom of the receiver. Where hydrogen is allowed to escape freely it carries with it an amount of the alkyl halid which is proportional to the vapor pressure of the alkyl halid at the temperature of the If ethyl iodid be used, substantial loss may be readily avoided, but where the more volatile alkyl halids, such as the bromids and chlorids are used an appreciable loss of the halids may result. Accordingly the reaction vessel in such cases should desirably have a volume sufliciently large to take care of all hydrogen evolved in the reaction'without exceeding the desired working pressure. By' suitable cooling upon completion of the reaction any material loss of the alkyl halid may be avoided.

While we have described our invention with reference to certain specific details it changes may be of the invention.

What we claim is: 1. The process of preparing lead tetraethyl which comprises subjecting an alloy 9 containing 20% sodium and 80% lead to the action of water in substantially equi-molecular proportion to the sodium, in the presence of ethyl iodid and in the absence of an organic catalyst, while maintaining the mass at substantially its boiling point.

2. The process of preparing lead tetraethyl which comprises subjecting an alloy of lead and sodium to the action of'wa-ter in substantially equi-m'olecular proportion to the sodium, in the presence of ethyl iodid, and in the absence of an organic catalyst, while maintaining the temperature at substantially the boiling point of the mass.

3. The process of preparing lead alkyl compounds which comprises subjecting a lead sodium alloy to the action of Water insubstantially equi-molecular proportion to the sodium in the presence of an alkyl halid, and in the absence of an organic catalyst, and maintaining the reaction mass under pressure.

4. The process of preparing lead alkyl compounds which comprises reacting upon a lead sodium alloy with Water in substantially equi-molecular proportion to the sodium, in the presence of an alkyl iodid and in the absence of an organic catalyst.

5. The process of preparing lead alkyl compounds which includes reacting upona 15 lead sodium alloy with Water in 'substan tially equi-molecular proportion to the soenemies A. KRAUS. counan c. capers. 

